For some time now, the amount of power consumed by servers has been increasing, as has the number of servers placed in various facilities. Servers today consume ten times more power than they did ten years ago. The U.S. Environmental Protection Agency estimated that in 2006 the nation's servers and data centers collectively consumed approximately 61 billion kilowatt-hours, or 1.5% of total U.S. electricity consumption, at a total cost of approximately $4.5 billion. This level represents a doubling in the level of energy consumption by data centers in the five years since 2001; and the level is expected to double again by 2011 as more and more applications shift from the desktop to a server-based computing paradigm. Already there are large server farms comprising a million or more servers.
The problem has grown to the extent that in California, for example, where twenty percent of the world's servers are currently located, data centers are drawing enormous power from the grids while parts of the state sometime endure blackouts. According to one expert specializing in the study of storage systems, these large clusters of power-hungry machines, along with rising energy prices, are generating huge energy bills, forcing data center owners nationwide to seek more energy-efficient solutions. An even bigger problem arises when the amount of available power in a facility is insufficient for companies to grow the number of servers required to meet demand. This server power management problem will increasingly impact companies' ability to scale their businesses, satisfy their customers, and optimize their operational efficiencies.
Driving the overall growth in server farms is the increased capacity required to run Internet-based businesses. In addition to the growth in traditional Web-based service providers, a revolution is currently taking place in the $120 billion software industry that will further drive the demand for server resources. Software applications that traditionally have been installed on personal computers are going online.
In addition to managing the power consumption of servers, power management is also important for battery-powered devices, such as laptops, smartphones, tablet computers, netbooks, etc., that have a limited amount of power available between chargings or battery replacement. While battery technology continues to improve, mobile devices are currently limited to less than 10 hours of use, and more typically, less than four hours of use, between chargings. Because charging mobile devices can be inconvenient, users want their devices to last longer between chargings.